Ask a Climatologist


Katharine Mach, co-director of science for the IPCC Working Group II based out of the Carnegie Institution for Science's Department of Global Ecology at Stanford University, is a scientist who worked on the latest IPCC report. She answers your questions about the earth and humans' vulnerability to climate change, what's already happened, will happen in the future and how we might fix this mess. Plus, anything else you've ever wanted to ask a climate scientist.

A Few Things We Learned from Dr. Mach

  • Climate change really is our fault:

“What we know is that the current change that we may see through the century with continued high emissions of greenhouse gases is really unprecedented in terms of the rate. You know, things that happened over millennia in the past, we might see over a century.”

  • A Geo-Engineered Solution?:

“Within the century, some of those techniques may become more common, especially bio energy paired with carbon capture and storage. Some of the other techniques really involve the manipulation of the amount of sunlight that’s entering into the atmosphere, sunlight deflection. And those in some cases will definitely – perhaps rather cheaply, reduce the amount of warming that the planet sees, but they come with trade-offs. So they affect the water cycle of the planet. They don’t reduce the amount of acidification that’s happening in our oceans. And kind of importantly, if you stopped that technique at any one point – if you stopped shooting particles into the stratosphere, warming could go up really rapidly, with potentially severe risks.” 

  • A Cost-Benefit Analysis:

“The report showed if we head toward some of the most ambitious mitigation scenarios, scenarios that would give us a very good chance of staying under a 2 degree C increase above pre-industrial levels – so that’s 3 and a half degrees Fahrenheit, we could get there – the models show – with only a shave off of annual economic growth of .06 percentage points. So that’s almost a rounding error. So a way of thinking of that is we could get to the total level of wealth in 2052 that we would [have gotten to] in 2050.”